Table 6. Top negation context features in a multi-corpus model, by chi-square value; and feature rank in domain-specific models.
| Feature Rank in Training Data | ||||||
| Feature Description | Chi∧2 | all | i2b2 | mipacq | negexts | sharp |
| (D) DepNeg path: dt_nmod_mod | 16713.1 | 1 | 5 | 1 | 2 | 1 |
| (A) Bag of 5 preceding words: no | 15601.1 | 2 | 1 | 3 | 3 | 2 |
| (E) Tree Fragment Context Above-Left: (DT no) | 15263.2 | 3 | 3 | 2 | 4 | 3 |
| (A) Bag of 10 preceding words: no | 14928.9 | 4 | 2 | 4 | 1 | 5 |
| (A) Bag of 3 preceding words: no | 14207.4 | 5 | 4 | 5 | 5 | 4 |
| (B) Preceding word #0: no | 10683.5 | 6 | 6 | 9 | 6 | 10 |
| (C) Cue category: no | 9848.3 | 7 | 7 | 6 | 12 | 6 |
| (C) Cue word: no | 8866.9 | 8 | 9 | 7 | 7 | 15 |
| (C) Cue phrase (any negation) | 8110.7 | 9 | 10 | 8 | 8 | 9 |
| (E) Tree Fragment Context Above-Left:(NP (DT no) (CONCEPT )) | 8038.3 | 10 | 8 | 18 | 13 | 23 |
| (D) DepNeg path: negverb->dobj_mod | 3817.3 | 11 | 12 | 13 | 16 | 285 |
| (E) Tree Fragment Context Above-Left:(VBZ semclass_deny) | 3809.4 | 12 | 13 | 10 | 15 | 851 |
| (A) Bag of 10 preceding words: denies | 3081.2 | 13 | 22 | 12 | 21 | 1195 |
| (E) Tree Fragment Context Above-Left: (DT any) | 2721.2 | 14 | 43 | 11 | 24 | 486 |
| (B) Preceding word #2: no | 2672.9 | 15 | 15 | 28 | 22 | 53 |
| (C) Cue category: deny | 2479.0 | 16 | 16 | 19 | 38 | 327 |
| (A) Bag of 5 preceding words: denies | 2380.3 | 17 | 28 | 16 | 26 | 2070 |
| (A) Bag of 5 following words: or | 2350.9 | 18 | 25 | 30 | 9 | 46 |
| (E) Tree Fragment Context Above-Left: (NP (DT no) (NML )) | 2247.9 | 19 | 27 | 44 | 34 | 19 |
| (A) Bag of 10 following words: or | 2242.1 | 20 | 26 | 29 | 10 | 39 |
Feature types are classified as in Section 3.4.